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Re: [RFC] lin-lwp.c prelim changes for new thread model
- From: Andrew Cagney <ac131313 at redhat dot com>
- To: Daniel Jacobowitz <drow at mvista dot com>,Michael Snyder <msnyder at redhat dot com>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Tue, 07 Jan 2003 19:33:00 -0500
- Subject: Re: [RFC] lin-lwp.c prelim changes for new thread model
- References: <3E1A14C5.77F6C2DF@redhat.com> <20030107033133.GB5132@nevyn.them.org>
Just an aside,
The minimal change I propose below is as follows:
When we send kill(SIGSTOP) to all the threads, we now include
the event thread, where previously we had made him a special case.
That way, whether in the new model or the old one, we can now do
a waitpid on every thread including the event thread.
What do you think?
To be honest, I don't like this very much. You're hurting performance
in the current case (whose performance is already quite bad enough,
thank you!). I don't think that the additional complexity/waiting is
At present GDB does ~60 system calls per multi-threaded single step (see
previous discussion related to ptrace), these extra two calls may easily
prove to be in the noise. Given the thread has already stopped, they
should be close to kernel no-ops.
When commenting on performance, the thing that is always needed is hard
data either supporting or dismissing any claim.